HP 48g Graphing Calculator - Manual (Page 22)

Whenever there is no cursor being displayed, pressing any of these six
keys executes the operation indicated by the colored label above them:
a
(or ( picture !) displays the current picture.
© (or ( sw ap )) swaps the objects on levels 1 and 2 of the stack,
(or
( stack ))
begins the Interactive Stack application.
(or
(VIEW 1)
puts the object on level 1 of the stack into its “best”
viewing mode (see page 2-10).
ill (or
( clear
)) clears the stack.
a (or ( drop )) drops the object on level 1 from the stack.
The CANCEL Key
When the HP 48 is on,
ON)
becomes the
(CANCEL
) key. Generally,
( cancel ) halts the current activity—so you can immediately start your
next task or recover from an unexpected situation.
To Stop the calculator:
■ To delete the command line, press
(CANCEL).
■ To cancel a special environment and restore the stack display, press
(CANCEL).
■ To cancel a running program, press
(CANCEL).
Menus: Extending the Keyboard
The HP 48 uses menus extensively to accommodate its hundreds of
built-in commands and functions.
A menu is a set of operations defined for the six blank menu keys at
the top of the keyboard. The current operations are described by the
six menu labels at the bottom of the display.
1-8 The Keyboard and Display